Only a small number of Saudi women appeared to take part in an organised protest against a driving ban after official threats of punishment.

Activists had urged women to get behind the wheel in defiance of the ban on female drivers in Saudi Arabia.

About 17,000 people have signed a petition calling for women to be allowed to drive, or at the very least, an explanation of why the ban should remain in force.

But ahead of the planned action, Saudi authorities women reported they had received phone calls from the interior ministry asking them to promise not to take part in the driving protest.

Undeterred by the warnings of unspecified sanctions and increased security in Riyadh, several women posted videos of themselves driving on Saturday.

At least four videos were posted on YouTube, including from the capital, and rights activist Naseema Assada said three others had driven in an eastern province to show women's "determination".

"Had there not been a threat from the interior ministry, more women would have responded," said Ms Assada, who did not herself drive so that "authorities would not consider the move a challenge" to the ministry orders.

More women are expected behind the wheel in the coming days if authorities take no measures against those who defied the ban on Saturday, activists say.

"The authorities clearly do not want any gatherings on a specific date," activist Maysaa al-Amudi said of the "drive-in".

"We are trying to calm things down and affirm that the campaign will continue but without a specific date."

Earlier this week, about 100 conservative clerics denounced the campaign as a threat to the country.

Activists behind it believe the public mood is changing, with many people - including an increasing number of men - publicly supporting women's right to drive.